How to check a blown fuse with a multimeter?

Car electrical problems often start with the simplest component – the fuse. When the radio doesn't work, lights don't turn on, or the cigarette lighter doesn't charge, the first step should be to check the fuses. In this guide, I will show you how to professionally diagnose a fault using a standard multimeter and how to perform a quick visual test.

What will you need?

To check fuses, you need a minimal set of tools:

• Digital multimeter - even the cheapest model for $5-10 is sufficient. Important: it must have a continuity test function (diode or speaker symbol)
• Fuse puller - usually found in the fuse box cover. If you don't have it, you can use small pliers (but not metal ones!)
• Flashlight - useful for illuminating the fuse box and visual inspection
• Fuse diagram - you'll find it in your vehicle's manual or in our FuseLayouts diagram database

Step 0: Locate the correct fuse

Before you start checking fuses, you need to know which one corresponds to the damaged device. Use our interactive FuseLayouts diagram database to find the correct fuse for your model. The diagrams show the exact location and description of each fuse.

Method 1: Visual Test (Quick verification)

The fastest method of checking a fuse, which requires no tools. However, it is less precise than a multimeter test.

Step-by-step instructions:

1. Turn off the ignition - for safety, turn off the engine and remove the key from the ignition
2. Pull out the fuse - use a plastic fuse puller or small pliers (don't use metal tools!)
3. Check against the light - look at the metal wire inside the plastic housing. Blade fuses have a wire in the shape of a U or S
4. Assess the condition:
   • ✅ Wire is continuous - the fuse is probably good
   • ❌ Wire is broken - the fuse is blown, needs replacement
   • ⚠️ Wire is scorched or dark - the fuse is damaged, needs replacement

Method 2: Multimeter Test (Professional and precise)

This is the surest diagnostic method. A multimeter allows you to check the continuity of an electrical circuit with 100% accuracy. Moreover, you don't even have to pull out the fuse if it has exposed test contacts on top of the housing (small metal points visible on the fuse's spine).

Step-by-step instructions:

1. Prepare the multimeter:
   • Turn on the multimeter
   • Set the dial to the diode/speaker symbol (continuity test, often marked as 🔊 or ➡️|)
   • Test the function - touch the probes together, you should hear a beep and see a value close to 0Ω
2. Test without removing the fuse (if it has test contacts):
   • Touch the black probe to one metal test point on the fuse's spine
   • Touch the red probe to the other metal test point
   • Make sure the probes have good contact with the metal
3. Test with the fuse removed (if it doesn't have test contacts):
   • Pull out the fuse using a fuse puller
   • Touch the probes to the metal legs of the fuse (one probe on each leg)
4. Interpret the result:
   • ✅ Continuous beep + value close to 0Ω - the fuse is good, the circuit is closed
   • ❌ Silence + value "OL" or "1" (infinity) - the fuse is blown, the circuit is open
   • ⚠️ Intermittent beep or unstable value - the fuse is damaged, needs replacement

Additional tips:

• Check both sides - some fuses may have different resistance values depending on the measurement direction (this is normal)
• Clean the contacts - if the multimeter doesn't respond, clean the metal points of the fuse (they may be corroded)
• Check the multimeter battery - a weak battery can give false readings

What to do after diagnosing a blown fuse?

If the fuse is blown, follow these steps:

1. Check the amperage - read the value on the fuse (e.g., "10A") or check the color (use our color table)
2. Find the cause - a blown fuse is a symptom, not a cause. Check if there's a short circuit in the circuit
3. Replace the fuse - use a fuse with exactly the same amperage and type (mini/standard/maxi)
4. Test - after replacement, check if the device works. If the fuse blows again, you have a short circuit

Common problems and solutions

Problem: Multimeter doesn't beep, but the fuse looks good

Solution: Check if the probes have good contact. Clean the metal surfaces. Make sure the multimeter is set to continuity test, not voltage measurement.

Problem: Fuse looks good, but the device doesn't work

Solution: This could be a micro-break invisible to the naked eye. Use a multimeter for verification. If the multimeter confirms the fuse is good, the problem may be elsewhere (damaged socket, short circuit in wires, damaged device).

Problem: Fuse blows immediately after replacement

Solution: This indicates a short circuit. Don't replace the fuse with a larger one! Check the wires, disconnect the device powered by this fuse, and check if the problem disappears. If so - the device is damaged.